I know there's already this question with many suggestions but it's marked as resolved and not about MBP.

I have a setup with Magic Keyboard and Trackpad 2 connected over Bluetooth to MBP. Also an external display Dell U2715H. I've been working for a few months with MBP 2012 and it worked flawlessly, the monitor was connected via DP to mDP cable. Then my 2012 MBP died on me and I replaced it with 2018 MBP. I connected the display via Satechi USB-C hub with mDP slot.

And with this new setup, my Trackpad started to suddenly drop Bluetooth connections from time to time. It randomly disconnects-connects for 4-5 times over a few seconds. So, it's obviously not a Trackpad or some Wi-Fi router interferences issue because it worked just fine with the old MBP. I tried a few things that did not help:

Uninstall LittleSnitch (I've read somewhere that it might interfere)

Connected USB-C hub to the right side (tried different slots)

Reset Bluetooth module

Disabled handoff

Connect/disconnect Bluetooth devices

Charged devices to 100%

Apple support wasn't helpful either.

At first, disconnects happened only with Trackpad but not Magic Keyboard which I thought is super weird but later the keyboard started to disconnect as well.

I read a few reports by people claiming that's the issue in the USB-C hub interfering with Bluetooth signal, so I tested a day without the USB hub and connections weren't dropped, so I decided that's the issue and bought myself a DP to USB-c cable to replace the hub for the display connection. But to my surprise, it did not help.

I installed Bluetooth PacketLogger and got these error logs during the disconnects:

I think the only helpful message out of all this is First packet of Higher Layer Message (i.e. start of an L2CAP packet). Sounds like there's an interference with Bluetooth after all.

At this point, I'm inclined to think that the MBP 2018 just has a bad Bluetooth module (or poor design that causes signal interferences) and to resolve it for good you'll need to buy an external Bluetooth adapter.

@Piero it seems like there's a telcom provider resides in the building nearby which causes interferences on Wi-Fi frequencies which it seems also used by Bluetooth. We had issues with our Wi-Fi connectivity which were resolved by replacing it to a 5Ghz router. Maybe it's just a coincidence that this started to happen when I bought new MBP but I think the Bluetooth module or just the construction, in general, are shitty in the new MBP.
– csandanovMay 7 at 4:41